Instant Way To Set Objects' Distance In Circular Pattern
Assuming all the vanes are separate objects, and you're in Object Mode..

The scaling of the center points isn't working because they are all already at 0.

Select all of the objects, and hit ShiftCtrlAltC > 'Origin to Geometry'. 

The scaling of the center points should now have an effect.
If you need the slight spiraling effect in the second picture, then. still manipulating center points only, rotate the objects in their common plane, about their common center.